1. Field
The present application relates to an apparatus and a method of fabricating a flat panel display device, to an apparatus and a method of fabricating a flat panel display device capable of detecting a broken line of a sealant in real time and of automatically repairing the detected broken line of the sealant.
2. Description of the Related Art
Recently, various types of flat panel display (FPD) devices have been developed that are smaller and lighter than cathode ray tube display devices. Such devices include a liquid crystal display (LCD) device, a field emission display (FED) device, a plasma display panel (PDP) and an electro-luminescence (EL) display device.
The FPD includes a flat panel in which cells are arranged in a matrix between two glasses, a printed circuit board module for driving the flat panel, and a case for protecting the flat panel and the printed circuit board module and integrating them. Since the LCD device is not a self-luminous device, the LCD device requires a separate light source such as a back light unit. Herein, the printed circuit board module receives red, green and blue image data, and a synchronizing signal from an exterior and then processes them to supply an image data, a scanning signal and a timing control signal to the flat panel. Such a printed circuit board module corresponds to a driving circuit making to normally display a computer image, a television image and the other available image on the flat panel.
A description of a LCD device will serves as an example of a FPD. The LCD device controls light transmittance of liquid crystal cells in accordance with video signals, thereby displaying pictures corresponding to the video signals on a liquid crystal display panel where liquid crystal cells are arranged in a matrix. To this end, the LCD device includes an active region where the liquid crystal cells are arranged in an active matrix, and a driving circuit for driving the liquid crystal cells of the active region.
Referring to FIGS. 1 and 2, a related art LCD device has a structure, in which an upper plate and a lower plate are faced to combine each other. The related art LCD device includes a picture display section 4 where liquid crystal cells are located, and a sealant 2 for combining the upper plate and the lower plate.
The picture display section 4 includes: the upper plate having a black matrix 20, a color filter 16 and a common electrode 14; and a lower plate facing to and combined with the upper plate and having a thin film transistor and a pixel electrode 22. Spacers 24 are formed between the upper plate and the lower plate. Also, a liquid crystal material 18 is injected into an inner space provided by the spacers 24 between the upper plate and the lower plate.
On the upper plate, the black matrix 20 is formed in a matrix on an upper substrate 11. The black matrix 20 serves to partition a surface of the upper substrate 11 into a plurality of cell regions at which the color filters 16 will be formed, and to prevent the interference of light between adjacent cells. Color filters 16 of the primary three colors, i.e., red, green and blue are sequentially formed on the upper substrate 11 where the black matrix 20 is formed. In this case, a material absorbing white light and transmitting only particular light with a specific wavelength, i.e., red, green or blue, is applied on an entire surface of the upper substrate 11 having the black matrix 20. Thereafter, the material is patterned, to thereby form each of the three color filters 16 of the primary three colors. A common electrode 14, a transparent conductive material having a ground electric potential supplied thereto, is formed on the upper substrate 11 where the black matrix 20 and the color filters 16 are formed. A polyamide is applied so as to cover the common electrode 14, to thereby form an upper alignment film 12.
The sealant 2 is formed at an outer line of the picture display section 4 in the upper plate to combine the upper plate and the lower plate.
In the lower plate, the TFT that switches the driving of the liquid crystal cell includes a gate electrode 25 extended from a gate line (not shown), a source electrode 28 extended from a data line (not shown), and a drain electrode 30 connected to a pixel electrode 22 through a contact hole 23. Further, the TFT includes a gate insulating film 6 to separately insulate the gate electrode 25, the source electrode 28 and the drain electrode 30; semiconductor layers 26 and 27 to form a conductive channel between the source electrode 28 and the drain electrode 30 by a gate voltage supplied to the gate electrode 25. Such a TFT selectively supplies a data signal from the data line to the pixel electrode 22 in response to a gate signal from the gate line.
The pixel electrode 22 is located at a cell area defined by the crossing of the data line and the gate line and is formed of a transparent conductive material with high light transmittance. The pixel electrode 22 is formed on a passivation film 8 applied to the entire surface of a lower substrate 1, and electrically connected to the drain electrode through the contact hole 23 formed in the passivation film 8.
After applying a lower alignment film 10 to an upper portion of the lower substrate 1 where the pixel electrode 22 is formed, a rubbing process is performed. Thereafter, the spacers 4 for maintaining a gap between the upper plate and the lower plate are sprayed to complete the lower plate.
Lastly, the upper plate and the lower plate separately made as described above are put into a desired position to combine them together by use of the sealant 2. Thereafter, the liquid crystal material is injected and is sealed, to thereby complete the LCD device.
As set forth above, the sealant 2, for combining the upper plate and the lower plate in the related art LCD device, formed on the upper plate, is formed by a sealing apparatus as shown in FIG. 3.
The sealing apparatus includes: a driver 60 facing the upper substrate 11 and executing horizontal movement and vertical movement; a guide line 70 for guiding the horizontal movement of the driver 60; a dispenser 72, installed at a lower end of the driver 60, for applying the sealant on the upper substrate 11; a supplier 62 connected to the dispenser 72 to supply the sealant; and a controller 64 for controlling the horizontal movement and the vertical movement of the driver 60.
The upper substrate 11 is reached by a loading device (not shown) on a stage 50. As described above, the black matrix 20, the color filter, and the common electrode of the picture display section 4 are formed on the upper substrate 11.
The driver 60 executes the horizontal movement along the guide line 70, in response to a control signal generated from the controller 64, or executes the vertical movement to correspond to the upper substrate 11.
The dispenser 72 applies the sealant 2 supplied from the supplier 62 to the upper substrate 11. To this end, a jet nozzle 74 is installed at one side of the dispenser 72 in order to supply the sealant 2 supplied from the dispenser 72 to the outer line of the picture display section 4 in a defined thickness and a defined width.
According to the related art sealing apparatus, when the upper substrate 11 is loaded on the stage 50, the driver 60 is lowered so as to have a designated gap between the jet nozzle 74 and the upper substrate 11 under a control of the controller 64. And then, the driver 60 executes the horizontal movement along the guide line 70. At this time, when the dispenser 72 is lowered so as to have the designated gap spaced from the upper substrate 11, the dispenser 72 supplies the sealant 2 from the supplier 62 to the net nozzle 74 in a designated pressure. Accordingly, as the driver 60 executes the horizontal movement, the jet nozzle 74 applies the sealant 2 supplied from the dispenser 72 in the designate pressure to the outer line of the picture display section 4 in the upper substrate 11 so as to have the designated thickness and the designated width.
However, in the related art sealing apparatus, when sealant 2 is applied, a broken line 80 occurs in the sealant 2 as shown in FIG. 3, due to the gap between the jet nozzle 74 and the upper substrate 11, a horizontal movement speed of the driver, the pressure exerted on the sealant 2 supplied from the dispenser 72 to the jet nozzle 74, and/or sudden clogging of the jet nozzle 74. Since the broken line 80 of the sealant 2 is inspected with the naked eye of a worker, the broken line 80 cannot be accurately detected. Meanwhile, if the broken line 80 of the sealant 2 is detected through the visible eyes of the worker, then the sealant 2 is applied again to the entire upper substrate 11. Thus, the related art sealing apparatus has a problem that a production yield is deteriorated because working hours of a sealing process become increased.